Claude Mythos Preview vs Mistral Medium 3 Instruct

Claude Mythos Preview (2026) and Mistral Medium 3 Instruct (2025) are frontier reasoning models from Anthropic and MistralAI. Claude Mythos Preview ships a 1m-token context window, while Mistral Medium 3 Instruct ships a 128k-token context window. On pricing, Mistral Medium 3 Instruct costs $0.40/1M input tokens versus $25/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Mistral Medium 3 Instruct is ~6150% cheaper at $0.40/1M; pay for Claude Mythos Preview only for coding workflow support.

Decision scorecard

Local evidence first
SignalClaude Mythos PreviewMistral Medium 3 Instruct
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsmultimodal apps and provider-routed production
Decision fitCoding, RAG, and AgentsLong context and Vision
Context window1m128k
Cheapest output$125/1M tokens$2/1M tokens
Provider routes2 tracked2 tracked
Shared benchmarks0 shared0 shared

Decision tradeoffs

Choose Claude Mythos Preview when...
  • Claude Mythos Preview has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Claude Mythos Preview uniquely exposes Reasoning, JSON / Tool use, and Structured outputs in local model data.
  • Local decision data tags Claude Mythos Preview for Coding, RAG, and Agents.
Choose Mistral Medium 3 Instruct when...
  • Mistral Medium 3 Instruct has the lower cheapest tracked output price at $2/1M tokens.
  • Local decision data tags Mistral Medium 3 Instruct for Long context and Vision.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate Mistral Medium 3 Instruct

Claude Mythos Preview

$51,250

Cheapest tracked route/tier: Anthropic

Mistral Medium 3 Instruct

$820

Cheapest tracked route/tier: Mistral AI Studio

Estimated monthly gap: $50,430. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Mythos Preview -> Mistral Medium 3 Instruct
  • No overlapping tracked provider route is sourced for Claude Mythos Preview and Mistral Medium 3 Instruct; plan for SDK, billing, or endpoint changes.
  • Mistral Medium 3 Instruct is $123/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Reasoning, JSON / Tool use, and Structured outputs before moving production traffic.
Mistral Medium 3 Instruct -> Claude Mythos Preview
  • No overlapping tracked provider route is sourced for Mistral Medium 3 Instruct and Claude Mythos Preview; plan for SDK, billing, or endpoint changes.
  • Claude Mythos Preview is $123/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Claude Mythos Preview adds Reasoning, JSON / Tool use, and Structured outputs in local capability data.

Specs

Specification
Released2026-05-012025-10-01
Context window1m128k
Parameters——
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2025-122025-03

Pricing and availability

Pricing attributeClaude Mythos PreviewMistral Medium 3 Instruct
Input price$25/1M tokens$0.40/1M tokens
Output price$125/1M tokens$2/1M tokens
Providers
AnthropicMicrosoft Foundry
NVIDIA NIMMistral AI Studio

Capabilities

CapabilityClaude Mythos PreviewMistral Medium 3 Instruct
VisionYesYes
MultimodalYesYes
ReasoningYesNo
JSON / Tool useYesNo
Structured outputsYesNo
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

No shared benchmark scores are currently available for this pair.

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Model pages
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.